Like a non-stick pan, the screen is coated with fluoropolymers, chains of carbon atoms with fluorine attached instead of the usual hydrogen.

The carbon-fluorine bond is incredibly stable, giving the coating very low surface energy: oily fingerprints wipe away, and your thumb gets that gliding feel. It also explains why a phone left face-down on the faintest slope will attempt escape.

Normal glass, like bottles and windows, is made from silica. Smartphone glass has aluminium woven into the silica network, stiffening the structure and helping it resist cracks.

Sodium ions are also added to the mix and sit in the gaps of the silica-alumina grid. The finished sheet is dipped into a 400°C potassium bath. The small sodium ions swap places with large potassium ones, squeezing into the structure, compressing the surface.

When an impact occurs, a crack must first push through this compressed layer.

Conductors have a bunch of free electrons that carry electricity, but they also reflect light. That’s a problem for something in front of a display, but indium tin oxide has a rare trick. It has just enough electrons to conduct without becoming a reflective electron-sea, making it both transparent and conductive.

It’s arranged as a whisper-thin grid and holds a tiny electric field. When your finger touches the glass above, it disturbs the field where it lands. A controller chip scans the grid hundreds of times a second, looking for those tiny changes and turning them into coordinates.

Every pixel is made of subpixels: microscopic red, green and blue lights, which blend in different amounts to make any colour on your screen. A light bulb needs to be connected to power, so a layer of transparent indium tin oxide carries power across the top, and a metal layer feeds power from below.

Left like this, the screen would just glow at full brightness. An expensive, big flat light. So, the subpixels sit on a layer of thin-film transistors: millions of dimmer switches, controlling the brightness of each pixel. Beneath it all, a final slab of glass protects the delicate filling.

The proximity detector and light sensor both use light-sensitive photodiodes, like tiny solar panels. The light sensor reads how bright the room is. The cheek detector sits behind an infrared filter, and an infrared LED shines out. When something is close it detects the light bouncing back.

In modern phones these sensors hide under the display, peeking through carefully engineered spots. It’s likely that the selfie camera will go the same way soon too. We’ll come back to cameras when we get to the back of the phone.

The captain’s other instruments survive too, shrunk into microelectromechanical systems: intricate working machines no larger than a matchstick head, with moving parts thinner than a human hair.

Like computer chips, they’re etched from silicon, carving out microscopic structures that bend, vibrate, and flex in response to the world.

The trick was powered by the phone’s accelerometer, which detects motion by measuring acceleration. Inside the chip, combs are suspended on microscopic springs. When the phone moves the combs shift, changing the gaps between the teeth. This alters an electrical charge, which the phone measures to track movement. Because gravity is always pulling down, the accelerometer can also tell which way is down.

Accelerometers alone are imprecise, which is where the gyroscope comes in. Instead of measuring straight-line movement, the gyroscope detects rotation with a vibrating structure. Moving things don’t want to rotate (the Coriolis effect), so as the phone turns, the mass pushes back a measurable amount.

There are three of each, packaged into a single chip. Together they give the phone six senses of motion, letting it rotate the screen, steer games, stabilise cameras, and pour the perfect fake pint.

The leap from telegraph to telephone was the microphone, converting sound into electrical signals that could travel along existing telegraph wires.

Inside your phone, a stretched membrane (think trampoline, but with the diameter of uncooked spaghetti), vibrates with sound. The phone measures those vibrations as an electrical signal.

Speakers reverse the process. An electromagnet moves a larger membrane back and forth, vibrating air to create sound.

Modern smartphones hide two speakers along their edges and scatter six to eight microphones throughout: one at the bottom for calls, others near the camera for video, and some away from your mouth to analyse and cancel out background noise.

To vibrate, modern smartphones use linear resonant actuators. An electromagnet rapidly moves a spring-loaded weight back and forth at its resonant frequency; the natural speed it wants to move, like pushing a swing at the right time.

It’s made of switches. Each switch, called a transistor, is binary. It can only be on or off, 1 or 0. Group those 1s and 0s together and they can stand for numbers, letters, colours and sounds, in the same way 26 letters can build every word, and the four bases of DNA can build every living thing.

Like a city, they are not spread evenly. They cluster into districts, each built for one kind of work. One does fast, step-by-step thinking. One drives the millions of pixels on your screen. The newest district is inspired by the neurones in your brain and can recognise faces and voices. Others serve as memory, and one guards secrets behind a locked door.

GPS goes to space, but it only receives timing signals. Mobile networks transmit over miles to connect you to a nearby mast. Wi-Fi is faster, but only across a house. Bluetooth links to nearby devices, and NFC works over a few centimetres to let you tap and pay.

They use different frequencies and data standards, but they all work the same way. The phone’s processor breaks data into tiny, self-contained packets, and its modem encodes these onto radio waves. Each packet carries a payload of data along with error-checking codes.

Your phone runs them all simultaneously, coordinating antenna sharing and managing interference. It’s a constant act of high-speed negotiation, and the reason turning on airplane mode saves so much battery.

Heat is bad for electronics, so phones have a radiator to spread and shed it. Most use thin graphite sheets, but if you’re fancy it might have a vapour chamber; water in a sealed metal box, which heats and evaporates, then cools and condenses on the far side.

Tiny thermometers monitor temperature. If things get too hot, they can slow down or even turn off the phone.

All that heating needs power. A lithium-ion battery stores electricity as chemical potential energy. Charging lifts lithium ions ‘uphill’, and they 'roll down' to power the phone.

We compare batteries by energy density, the energy they can store for their weight. Your phone’s battery can store around 270 watt-hours per kg, four times that of the 90s NiMH batteries.

Petrol stores 50 times more energy by weight, but it needs to be exploded. A doughnut stores around 15 times, but it needs to be digested.

Your phone’s battery has the energy density of a boiled potato, but what makes it special is that it releases its energy smoothly as electricity, no engine or digestion needed, and that it can be recharged hundreds of times over its lifetime.

Early phone buttons were grim. Squishy rubber that wobbled under your fingers and needed a deliberate press. Over the years they became crisper, using a thin metal dome which snaps back into shape to produce a crisp, familiar click.

Then the rise of the touchscreen made physical buttons an endangered species. Only three survivors remain: volume up, volume down, and the wake button. Everything else has been swallowed by glass.

The photodiodes are microscopic, 30 times smaller than screen pixels and sit beneath red, green and blue filters, each measuring one slice of the colour spectrum.

Above them sit a stack of lenses to correct distortion, colour fringing and softness. One lens group can move with tiny motors, stabilising the image.

We haven’t yet cracked white LEDs. Instead, your phone uses a blue gallium nitride LED, with a phosphor coating that makes some of the light yellow. The yellow and blue mix to make white.

In the 2000s, some feature phones included a small LED torch at the top. When cameras arrived, the LED moved to the back, flashing for photos. Manufacturers inexplicably hid the switch for a while, and dodgy flashlight apps proliferated. Today, it's a single swipe from the lock screen.